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United States Patent | 5,566,099 |
Shimada | October 15, 1996 |
A pseudorandom number generator which uses linear feedback shift registers and a nonlinear function circuit and can make the conditioned output distribution of generated pseudorandom numbers uniform even if the conditioned output distribution of the nonlinear function circuit has some deviation. The generator has a shift register to which the output of the nonlinear function circuit is inputted as a serial input, an initial value setting circuit for setting random initial values to the linear feedback shift registers and the shift registers, and an adder for adding predetermined bits of the parallel outputs of the register and outputting a pseudorandom number stream. The generator can be used to generate a cryptogram which cannot be deciphered by the correlation attack method.
Inventors: | Shimada; Michio (Tokyo, JP) |
Assignee: | NEC Corporation (Tokyo, JP) |
Appl. No.: | 310998 |
Filed: | September 22, 1994 |
Oct 06, 1993[JP] | 5-274935 |
Current U.S. Class: | 708/250; 331/78; 380/46; 708/252 |
Intern'l Class: | G06F 001/02; H04L 009/00; H03B 029/00 |
Field of Search: | 364/717 331/78 380/46,20 |
4760559 | Jul., 1988 | Okamoto et al. | 380/48. |
5046036 | Sep., 1991 | Tezuka | 364/717. |
5218559 | Jun., 1993 | Angebaud et al. | 364/717. |
5323338 | Jun., 1994 | Hawthorne | 364/717. |
5434807 | Jul., 1995 | Yoshida | 364/717. |
Philip R. Geffe, "How to protect data with ciphers that are really hard to break", Electronics, Jan. 4, 1973, pp. 99-101. T. Siegenthaler, "Correlation-Immunity of Nonlinear Combining Functions for Cryptographic Applications", IEEE Transactions on Information Theory, vol. IT-30, No. 5, pp. 776-780 (Sep. 1984). Eiji Okamoto, "Introduction to Cryptograph Theory", Kyoritsu Shuppan Kabusiki Kaisya (1993) (ISBN 4-320-02633-0). |